A pilot study of camrelizumab with docetaxel and cisplatin for the first line treatment in recurrent/metastatic oral squamous cell carcinoma

Abstract Pembrolizumab with cisplatin and 5‐fluorouracil showed survival benefit but relatively high occurrence of treatment‐related adverse events (TRAEs) for recurrent/metastatic oral squamous cell carcinoma (R/M OSCC). A more tolerable regime is needed. This trial enrolled 20 R/M OSCC patients with previously untreated and PD‐L1 positive. Patients were administered camrelizumab with docetaxel and cisplatin every 3 weeks for six cycles, followed by camrelizumab monotherapy every 3 weeks until disease progression or intolerable toxicity. The primary endpoint was occurrence of grade ≥ 3 TRAEs, secondary endpoints included overall survival (OS), progression‐free survival (PFS), and overall response rate (ORR). 45% patients experienced grade ≥ 3 TRAEs, which the most common were anemia (15%), stomatitis (15%), and neutropenia (10%). The most common potential immune‐related adverse events were reactive cutaneous capillary endothelial proliferation (RCCEP; 60%), hypothyroidism (35%), and pneumonitis (15%). No treatment‐related deaths occurred. The median OS, PFS, and ORR was 14.4 months, 5.35 months, and 40.0% respectively. The study also found RCCEP occurrence, lower FOXP3+ cells, and higher density of intratumor tertiary lymphoid structure were associated with improved efficacy. Our data suggest that camrelizumab with docetaxel/cisplatin as first‐line therapy was well tolerable and had potentially favorite efficacy in PD‐L1‐positive patients with R/M OSCC.


CSCO-Hengrui Oncology Clinical
Research Funding, Grant/Award Number: Y-HR2019-0428 tolerable and had potentially favorite efficacy in PD-L1-positive patients with R/M OSCC.

K E Y W O R D S
camrelizumab, first-line treatment, immunotherapy, oral cancer INTRODUCTION Oral squamous cell carcinoma (OSCC) is frequent subtype malignancies in the head and neck region. 1 Despite undergoing curative surgery, radiotherapy, and/or chemotherapy, patients with OSCC have a relatively high incidence of recurrence and metastasis. 2 The median overall survival (OS) time for recurrent and/or metastatic (R/M) patients with OSCC is 8-10 months. 3 Anti-programmed cell death protein 1 (PD-1) immunotherapy enhances the immune response to tumors and impairs the growth of cancer cells. 4 It is rational for the combination between anti-PD-1 immunotherapy and chemotherapy for that chemotherapy promotes immunogenic cell death, enhances the release of tumor antigens, and accelerates immune response. 5 The KEYNOTE-048 study revealed that pembrolizumab combined with PF regimen chemotherapy (cisplatin/5-fluorouracil) in the total population improved OS compared with EXTREME regimen (cetuximab plus cisplatin/5-fluorouracil) for patients with R/M head and neck squamous cell carcinoma (HNSCC). 6 However, 72% of enrolled patients in the pembrolizumab with PF regimen chemotherapy experienced grade 3 or higher treatment-related adverse events (TRAEs, defined as adverse medical events potentially related to the treatment that occurs during clinical trial), and 12% patients experienced AEs leading to death. 6 TPEXTREME trial showed that patients with R/M HNSCC who adopted TPEx (cetuximab, docetaxel, and cisplatin) regimen had no inferior efficacy but fewer AEs (defined as adverse medical events that occurs during clinical trial) of grade 4 or worse (36 vs. 52%) compared with patients with EXTREME (cetuximab, 5ŋfluorouracil, and cisplatin) regimen, 7 suggesting a lower toxic chemotherapy regimen in R/M HNSCC. Besides, OSCC is a highly immunodeficient tumor with an immunosuppressive tumor microenvironment. 8 Docetaxel was reported to convert immunosuppressive tumor microenvironment by facilitating tumor-associated macrophage to repolarize from M2-like to M1-like phenotype and reducing circulating myeloid-derived suppressor cells (MDSCs). 9,10 Therefore, TP regimen chemotherapy might be suitable for OSCC patients.
PDŋ1 ligand 1 (PDŋL1) expression was reported to be positively correlated with response to immunotherapy. 11 Combined positive score (CPS), a variant reflects the PD-L1 expression, defined as the number of PDŋL1-positive tumor cells and associated immunocytes/the number of total tumor cells×100, predicted prognosis for pembrolizumab therapy in patients with HNSCC. 12 It suggested that PDŋL1-positive OSCC patients may have a better prognosis by immunotherapy.
Camrelizumab is a high-affinity PD-1 antibody that exerts antitumor activity with considerate safety in various types of malignancies. 13,14 Previous study has preliminarily investigated the efficacy of camrelizumab combined with VEGFR2 inhibitor apatinib in the neoadjuvant therapy for locally advanced resectable OSCC. 15 However, the efficacy and safety of camrelizumab with chemotherapy in R/M OSCC has never been investigated.
Here, we conducted an open-labeled, single-arm, phase Ib trial to explore safety and efficacy of camrelizumab plus TP (docetaxel/cisplatin) regimen chemotherapy as a first-line therapy for patients with R/M OSCC. We showed that camrelizumab with docetaxel and cisplatin exerted favorite efficacy and tolerable toxicity in patients with R/M OSCC. Besides, we further investigated tumor immune microenvironment in the enrolled patients and found potential predictive biomarkers of immunotherapy in patients with R/M OSCC.

Clinical characteristic of enrolled patients
Between July 14, 2020 and October 8, 2021, 24 patients with recurrent/metastatic oral squamous cell carcinoma (R/M OSCC) were screened, and 20 eligible patients were enrolled. The median follow-up duration, defined as the interval between the study enrollment and cut-off date or death, was 18.5 months as of the data cut-off date (November 1, 2022). Most patients (18 out of 20, 90%) discontinued the treatment due to disease progression (n = 10), patient withdrawal (n = 4), and AEs (n = 4). Among four withdrawn patients, one patient achieved partial response (PR) but requested discontinuation and returned to local hospital for maintenance treatment; three patients were unsatisfied with the treatment effects (efficacy assessed F I G U R E 1 Trial profile of the study. stable disease) and received palliative surgical resection ( Figure 1). Participants baseline characteristics are presented in Table 1. Most patients presented with locally recurrent disease (17 out of 20, 85.0%) and HPV-negative status (19 out of 20, 95%).

The efficacy and clinical outcome of patients
Ten (50%) deaths occurred on the cut-off date (November 1, 2022). The median OS was 14.4 months (95% CI 8.8−20.0 months) (Figure 2A). The median progression-free survival (PFS) was 5.35 months (95% CI 4.0−6.6 months) ( Figure 2B). Overall, one patient had a complete response (CR), seven patients had a confirmed PR, six patients had confirmed stable disease (SD), and six patients had confirmed progressive disease (PD). The objective response rate (ORR) was 40.0% (eight out of 20; 95% CI 19.1−63.9%), TA B L E 2 Adverse events potentially related to the treatment.
A previous study reported that the incidence of RCCEP correlated with camrelizumab efficacy in patients with advanced hepatocellular carcinoma. 16 In our study, among 12 patients with RCCEP, eight patients achieved PR or CR, four patients achieved SD, and no patients without RCCEP achieved PR or CR. The occurrence of RCCEP was significantly associated with improved median PFS  Figure 4F) were observed. Previous study suggested that p16 expression was correlated with the positive expression rate of PD-L1. 17 However, as only one patient was p16 positive in our study, the association between p16 status and PD-L1 expression could not be reached. The patient diagnosed with tongue cancer with lung metastasis but without local recurrence. The patient achieved PR and continued the treatment by the cut-off date.

The potential biomarkers of immune microenvironment
Baseline tumor sections were eligible from 17 enrolled patients to analyze the tumor immune microenvironment. The expression of FOXP3 was significantly higher in nonresponders (patients with SD/PD) than responders (patients with CR/PR) ( Figure 5A). However, no significant differences were observed in the expression of CD4, CD8, CD68, CD163 and TGFβ1 between responders and nonresponders ( Figure 5A). For tertiary lymphoid structure (TLS) analysis, patients with higher TLS density had significantly higher response rate in intratumor TLS (defined as TLS in core tumor area) than those with lower TLS density ( Figures 5B and C). However, there was no significant correlation between peritumoral (defined as TLS in invasive margin of tumor, which was more than 0.5 mm adjacent to the tumor; Figure 5D) or total ( Figure 5E) TLS and response rate.

DISCUSSION
Our study provided the first evidence that camrelizumab combined with TP regimen chemotherapy was well tolerated and indicated potentially improved median OS, PFS, and ORR in the first-line treatment of patients with R/M OSCC compared with the efficacy of cetuximab and/or chemotherapy reported by previous studies. Patients with R/M HNSCC have been shown to benefit from PD-1 inhibitor therapy. The KEYNOTE-040 and CheckMate 141 studies have indicated that patients with R/M HNSCC obtained survival benefit by receiving pembrolizumab or nivolumab as second-line therapy compared with standard second-line therapy. 18,19 Currently, cisplatin/5-fluorouracil (PF) and docetaxel/cisplatin are the preferred chemotherapy regimens for patients with R/M HNSCC. Nevertheless, chemotherapy in PF regimen seemingly exerted a higher toxicity than TP regimen. In the KEYNOTE-048, 85% of patients receiving pembrolizumab plus PF regimen chemotherapy experienced grade 3 or higher AEs, and 12% of patients died due to AEs. 6 E1395 trial showed no survival difference between cisplatin plus paclitaxel and cisplatin plus fluorouracil in patients with advanced head and neck cancer but a significantly lower incidence of grade 3 or more AEs (80 vs. 97%) in the cisplatin plus paclitaxel group. 3 The TPEXTREME trial showed no survival difference (median OS, 14.5 vs. 13.4 months; HR 0.89 [95% CI 0.74−1.08]; p = 0.23) but a lower incidence of grade 3 or higher AEs (81 vs. 93%, p < 0.0001) in patients with R/M HNSCC administered cetuximab, docetaxel, and cisplatin compared with cetuximab, 5ŋfluorouracil, and cisplatin. 9 As a result, we adopted a docetaxel/cisplatin-based regimen as the chemotherapy in this study. In our study, 50% of patients experienced grade 3 or higher TRAEs, suggesting a possibly less toxic chemotherapy regimen compared with pembrolizumab plus PF regimen chemotherapy in R/M OSCC.
Several studies have reported that irAEs are potentially associated with tumor response in patients receiving immune checkpoint blockade. 20 RCCEP, a special and most common irAE only observed in patients treated with camrelizumab, was a skin lesion manifested as a red spot or nodules that tended to rupture and bleed. 21 Wang et al. 22 reported that RCCEP occurrence was positively associated with better mPFS, mOS, and ORR of camrelizumab in patients with advanced hepatocellular carcinoma. Our results also found significant association between the occurrence of RCCEP and better ORR, PFS, and OS benefit, suggesting that RCCEP might act as an independent prognostic factor of camrelizumab treatment in patients with R/M OSCC. Among those camrelizumab nonspecific irAEs, the most common irAE was hypothyroidism, which occurred in 35% participants. This result was also similar with the previously reported irAEs not only for camrelizumab, 23,24 but also for pembrolizumab and nivolumab. 21,25 The KEYNOTE-048 trial revealed that pembrolizumab plus PF regimen chemotherapy (platinum/5-fluorouracil) prolonged median OS in the total population and in CPS ≥ 1 population compared with standard first-line treatment in patients with R/M HNSCC. However, primary site of HNSCC patients would affect the efficacy of anti-PD1 immunotherapy. Kate Clancy et al. 26 reported that R/M OSCC patients have a poorer OS than oropharyngeal and laryngeal patients who receiving pembrolizumab or nivolumab. Numerous studies have found that anti-PD1 immunotherapy could be enhanced in patients with high PD-L1 expression in the tumor microenvironment in certain malignancies, including HNSCC. 27,28 In our study, the median was 14.4 months (95% CI 9.9−18.9 months) in CPS ≥ 1 patients with R/M OSCC who were administered camrelizumab plus docetaxel and cisplatin as first-line therapy, suggesting significant survival benefit in CPS ≥ 1 population with R/M OSCC compared with cetuximab and/or chemotherapy. Furthermore, the median PFS was 5.35 months (95% CI 4.0−6.6 months), and the ORR was 40.0% (95% CI 19.1−63.9%), indicating a similar antitumor activity with pembrolizumab plus PF regimen chemotherapy.
In the KEYNOTE-048 study, pembrolizumab plus PF regimen chemotherapy improved the median OS to 14.7 months, median PFS to 5.8 months, and ORR to 43% in patients with R/M HNSCC having a CPS ≥ 20. 6  HPV status was reported to be associated with the positive expression rate of PD-L1. 17 In our study, the patient with p16 positive showed a favorite efficacy to the treatment. However, with the overall small sample size, the association between HPV status and PD-L1 expression level could not be reached, and it deserves further investigation in the future.
In our study, we observed higher expression of FOXP3 + cells infiltration in responders at baseline, indicates higher infiltration of Tregs may affect the response therapeutic effect in patients with R/M OSCC. Consistent with previous studies, CD4 + T cells, CD8 + T cells, CD68 + , CD163 + , and TGFβ1 + cells showed no significant correlation with the response rate at baseline. Recently, TLS was identified as a predictive biomarker of immunotherapy, but the location of TLS affected the response to immunotherapy distinctively. Our results found a positive association between density of intratumor TLS and response to camrelizumab with docetaxel/cisplatin treatment, suggested that TLS localized to the core of tumor might predict the efficacy of immunotherapy.
Our study had several limitations, including a singlearm study design and a relatively small sample size. Additionally, the adoption of an open-label, single-center study needs confirmation by a multicenter, randomized, double-blind trial. Additionally, the study was underpowered for the subgroup analysis of efficacy based on PD-L1 status and RCCEP occurrence.
In conclusion, camrelizumab plus docetaxel and cisplatin as first-line therapy demonstrated tolerable TRAEs occurrence and potentially favorable antitumor activity in patients with R/M OSCC. Our data suggest that camrelizumab plus TP-regimen chemotherapy is a promising first-line therapy for R/M OSCC, and further a large scale randomized, double-blind trials are required.

Study design
The CHANCE study was an open-label, single-arm, phase Ib trial conducted at Shanghai Ninth People's Hospital. The inclusion criteria for eligible patients were: aged 18-75 years; histologically diagnosed as R/M OSCC with no surgical indication; had sufficient tumor sample for PDŋL1 and HPV status (HPV-positivity was defined as tumors that were p16 positive by immunohistochemistry (IHC) staining (clone E6H4; CINtec histology kit; Roche diagnostics)) testing; CPS ≥ 1; had measurable lesion according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 29 ; had an score of Eastern Cooperative Oncology Group (ECOG) ≤ 1; had a clearance of serum creatinine > 60 mL/min to receive cisplatin exposure; and had acceptable bone marrow, cardiac, liver, and renal functions. Exclusion criteria included previous systemic therapy for HNSCC after metastasis or recurrence; had surgical operation or radiotherapy within 6 weeks before screening; had a cumulative dose of cisplatin > 300 mg/m 2 ; had a history of other malignancies within 5 years before study entry, except for cured skin basal cell carcinoma, skin squamous cell carcinoma, carcinoma in situ of the cervix and early prostate cancer; had active or a history of autoimmune disease; administrated immunosuppressive drugs or systemic hormone therapy with a dose of 10 mg or more per day, and still continuing within 2 weeks before screening; previously treated with CTLA-4, PD-1, or PD-L1 antibodies; active or uncontrollable brain metastases; human immunodeficiency virus or treponema pallidum infection; persistent or active infection requiring intervening; and active pulmonary disease (asthma, obstructive pulmonary disease, and interstitial pneumonia) or had a history of active pulmonary tuberculosis.
The protocol of trial was reviewed and approved by the ethics committee of the Shanghai Ninth People's Hospital (SH9H-2019-T354-3), and the trial was done following the guidelines of Declaration of Helsinki and Good Clinical Practice. Written informed consents were signed before study entry. The study was registered in the Chinese Clinical Trial Registry (ChiCTR1900026736) and also registered in ClinicalTrials.gov (NCT05611463).

Procedures
Patients were administered camrelizumab (200 mg) on day 1 with docetaxel (75 mg/m 2 ) and cisplatin (75 mg/m 2 ) on day 2 every 3 weeks for a maximum of six cycles, then followed by camrelizumab monotherapy every 3 weeks.
The dose of camrelizumab based on the phase I trial of camrelizumab in solid tumors. 21 The treatment continued until disease progression, intolerable toxicity, or patientinitiated withdrawal. Participants with unconfirmed disease progression that clinically stable could continue the treatment until progression was confirmed by imaging 4 weeks later. Camrelizumab was paused if grade 2 of TRAEs occurred and continued until the grade of TRAEs dropped to 0 or 1 within 12 weeks. Camrelizumab was permanently discontinued if grade 3 or worse TRAEs occurred or grade 2 of TRAEs failed to recover to 0 or 1 within 12 weeks. The dose of docetaxel and cisplatin was allowed to reduce to 60 mg/m 2 if grade 3 or worse TRAEs occurred in the last cycle and recovered to grade 0 or 1 within 6 weeks, and permanently discontinued if failed to recovered to grade 0 or 1 within 6 weeks. Tumor imaging was evaluated by using computed tomography and magnetic resonance imaging. The assessment was conducted at baseline, every two cycles through the first year since study entry, and every 3 months since the second year. The response to treatment was determined according to the revised Response Evaluation Criteria in Solid Tumors (RECIST version 1.1), 30 and toxicity was recorded each week during and after the therapy in accordance with the Common Terminology Criteria for Adverse Events (version 5.0). Survival information was obtained from participants every 3 months during follow-up.

IHC and multiplex immunofluorescence analysis
Baseline tumor biopsy was obtained from metastatic or recurrent lesions within 6 months before enrollment. CPS, measured by using the PDŋL1 IHC 22C3 assay (Agilent Technologies, Santa Clara, CA, USA), was adopted to evaluate PDŋL1 expression. We defined CPS ≥ 1 as PD-L1 positive.

Outcomes
The primary endpoint was occurrence of grade ≥ 3 TRAEs, defined as the proportion of participants with grade 3 or worse TRAEs. TRAEs were collected to access safety and tolerability during the treatment period and 1 month after treatment withdrawal or 3 months if serious adverse events occurred. TRAEs were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) version 5.0. 22 Secondary endpoints for the study were OS, defined as time between study enrollment and death from any cause; ORR, defined as the proportion of participants with PR or CR according to RECIST (version 1.1) assessed by a specialized radiologist and confirmed by two other masking radiologists; PFS, defined as time between enrollment and the first disease progression or death from any cause, whichever occurred first; and DOR, defined as interval from the first time participants achieve CR or PR to the first evaluation of PD.

Statistical analysis
Sample size was calculated by performing PASS version 14.0.3. The trial was assumed that 72% patients with R/M OSCC receiving PF (cisplatin+5-fluorouracil) regimen chemotherapy experienced grade 3 or worse TRAEs. 3 The occurrence of grade 3 or worse TRAEs was assumed to decline 1/3 to 48% with the therapy of camrelizumab to TP regimen chemotherapy. Patients were accrued for 24 months and followed up for an additional 18 months. The study designed a power of 80% to detect a difference, and a 10% (one-sided) type I error rate. We calculated a minimum sample size of 18 patients, and we planned to accrue 20 patients by assuming a 10% drop-out rate. The secondary endpoints (OS, PFS, and DOR) were analyzed by Kaplan-Meier method with corresponding 95% CIs for the median estimation. Subgroup analyses including the occurrence of reactive cutaneous capillary endothelial proliferation (RCCEP) and CPS PD-L1 ≥ 20 were accessed by performing Mann-Whitney test. The correlation between TIL, TLS, and response was analyzed by Student's t-test. p Value < 0.05 was defined as statistically significant. The cut-off date for this study was November 1, 2022.

A U T H O R C O N T R I B U T I O N
Guoxin Ren and Jingzhou Hu designed the study. Houyu Ju, Dongliang Wei, and Qi Ding obtained and interpreted the data. Houyu Ju, Mengyu Rui, and Yunteng Wu drafted the manuscript. Yang Liu and Zongyu Fan performed statistical analysis. Yanli Yao and Guoxin Ren revised the manuscript. All authors read and approved the final manuscript.

A C K N O W L E D G M E N T S
The authors thank the patients and their families for participating in this study. We also thank Jiangsu HengRui Pharmaceuticals Co., China, for kindly providing the anti-PD-1 antibody camrelizumab for free of charge. This work was supported by the Clinical Research Booster Program of Shanghai Ninth People's Hospital (JYLJ202020), National Nature Science Foundation of China (grants 81902748), and the CSCO-Hengrui Oncology Clinical Research Funding (grant Y-HR2019-0428).

C O N F L I C T O F I N T E R E S T S TAT E M E N T
All the authors have no potential conflict of interest.

D ATA AVA I L A B I L I T Y S TAT E M E N T
Data are available upon reasonable request to the corresponding author.

E T H I C S S TAT E M E N T
This study was registered in the Clinical Trial Registry (NCT05611463) and approved by the Institutional Review Board of Shanghai Ninth People's Hospital affiliated to Shanghai Jiao Tong University School of Medicine. The study was conducted in accordance with the Declaration of Helsinki and Good Clinical Practice. Written informed consents were obtained from all patients before participated.